tDCS is a noninvasive brain stimulation technique that utilizes low amplitude direct currents applied via scalp electrodes to modulate the level of cortical excitability.Several studies have demonstrated that tDCS applied over the sensory-motor cortex has been able to decrease pain sensation and to increase pain threshold in healthy subjects and in chronic pain patients. The aim of this study was to test whether daily sessions of anodal tDCS repeated for 5 consecutive days may be effective in reducing pain in a large number of chronic pain patients. The cathode is usually applied over the right forhead above the eye. The aim of the study is to test whether daily sessions of tDCS repeated for 5 consecutive days will influence on ophthalmologic parametrs.